364 TEANSACTIONS LIVEEPOOL BIOLOGICAL SOCIETY. 



tion in a 10 % solution of nitric acid, and staining in a 

 rather weak solution of borax carmine, the specimens 

 remaining in the solution for from two to three days. 



I think it advisable to preface my description of the 

 specimens from Port Erin by stating the characters of the 

 genus, and those by which the three British species are 

 distinguished by Prof. Bell in his " Catalogue of British 

 Echinoderms in the British Museum," published in 1892. 

 Genus Stjnapta : Tentacles ten to twenty-five ; deposits 

 anchors, anchor plates, and fine granules ; hermaphrodite. 



Synapta inhcerens. Twelve tentacles, each with six or 

 seven digitate processes on either side ;* a single madre- 

 poric canal ; one to three Polian vesicles ; edge of fluke 

 of anchor serrated ; several of the anchor plates with 

 serrated holes ; miliary granules not largely developed. 



Synapta buski. Eleven tentacles, with three true 

 digits and two or three transverse ridges which look like 

 digits ; a single madreporic canal ; one Polian vesicle. 

 Anchor plates with seven dentate holes, and long narrow 

 handle. 



Synapta digitata. Twelve tentacles, each with four or 

 five digitate processes on either side ; a single madreporic 

 canal and Polian vesicle. Fluke of anchor smooth or 

 slightly serrated ; the holes of the anchor-plates smooth 

 or with fainter serrations than in S. inhcerens ; miliary 

 granules numerous and in places crowded. 



Several inconsistencies between these definitions and 

 the figures which adorn the plates of the Catalogue impair 

 the usefulness of both. S. inhcerens is said to have 

 '' several " of the anchor plates with serrated holes ; while 

 each of the five plates figured have serrated holes. S. 



* Prof. Theel, in Lis Report on the Holotlmroidea of the "Challenger" 

 Expedition gives the number of digitate processes on the tentacles of S. inhce- 

 rens as from twelve to fifteen. 



