Koinocystididae and Gnathorhynchidae (Platyhelminthes: Rhabdocoela: Kalyptorhynchia) from the Galapagos, with the description of three new species Author Reygel, Patrick C. Author Willems, Wim R. Author Artois, Tom J. text Zootaxa 2011 3096 27 40 journal article 46005 10.5281/zenodo.200746 7bf9fd11-d56f-40a9-9ae6-ebc115ab791b 1175-5326 200746 Itaipusa divae Marcus, 1949 ( Fig. 3 ) New localities in the Galapagos. Santa Cruz Island, stations IX6 b, IX5 b (both rock pools), IX6 a (sandy beach); Baltra, station X3 (fine-grained sand); Barrington, stations XI1 and XI2 (fine-grained sand). New localities outside the Galapagos. Several localities in Curaçao ( Netherlands Antilles ): Spaanse Water, Isla Grandi ( N 12°04'57.21" , W 68°51'21.21" ), detritus-rich sample taken from a littoral sea grass bed ( Thalassia testudinum ) at the eastern side of the most narrow point of the peninsula ( Dec. 14, 1998 ); Dam di Cabicuchi (between the Caracasbaai and the Spaanse Water, N 12°04'39.57" , W 68°51'48.89" ), on Thalassia testudinum with smaller epiphytic algae ( Dec. 14 & 30, 1998); Playa Canoa ( N 12°10'30.65" , W 68°51'55.19" ), on small brown algae taken from the sheltered side of the narrow spit of land that protects the beach ( Dec. 28, 1998 ). Known distribution. Two localities in Baia de Santos ( Brazil ) (see Marcus 1949 for details). Material. Galapagos: two individuals studied alive, nine serially-sectioned ones ( ZMUG 23280-23288). Curaçao : several individuals studied alive, five whole mounts, two serially-sectioned specimens (HU IV.4.11-IV.4.17). Remarks. The general organisation of our specimens corresponds well with the observations by Marcus (1949) , including the fact that the epidermis is syncytial. As mentioned earlier by Karling (1980) the exact course of the female duct is hard to discern. In both live and sectioned animals, the numerous small hooks on the sclerotized folds of the cirrus are longer than the 2 µm mentioned by Marcus (1949) . The pictures (see Fig. 3 B for one of them) of the two specimens from Galapagos show hooks with a length of ± 4 µm on all sclerotized folds. This is also the case in the specimens from Curaçao , with exception of one specimen that shows a few areas of the sclerotized folds with smaller hooks (1−2 µm). On the syntype , Karling (1980) observed some areas with rather large hooks (4−7 µm). This observation indicates that, possibly depending on the area of cirrus, the hooks may vary in length between 1 and 7 µm. In the Galapagos specimens studied alive, the course-grained basophilic prostate ducts have a more saccular appearance. In the sectioned material of both the Galapagos and Curaçao , the exact form of the ducts is not well visible, except in two specimens from Galapagos where these ducts are filiform, at least in the distal part of the prostate vesicle. Pictures of the Galapagos specimens reveal large (secretion?) granules scattered around the distal part of the ejaculatory duct, which could not be found again in the sectioned material. Nevertheless, in all sectioned specimens some ill-defined, fine-grained, eosinophilic secretion could be observed near to the distal part of the prostate ducts.