56 Scientific Proceedings, Royal Dublin Society ^ 



sensory buds were present. The plates had dissolved away before examina- 

 tion ; but 4 anchors measuring from 165 to 220/x. measured 132/a across the 

 flukes. No giant anchors were seen. The specimens from Clare Island were 

 in good condition, and measured ca. 16 mm., less tentacles. No giant anchors 

 could be seen with a lens on either, nor were there any present in 3 rings of 

 epidermis taken from various parts of the body. The anchors and plates 

 seem to be veiy typical of the usual shallow water type. A ring of skin of 

 15 mm. in length by ca. 3 mm. in depth, taken from the anterior portion of 

 body, shows ca. 95 anchors pointing their flukes in one horizontal direction, 

 and ca. 62 to the other, while a very few directed their flukes up or down 

 vertically. Part of the preparation was too opaque to enable all the anchors 

 to be noted. Usually those placed side by side on the strip of skin all point 

 in the same direction, with their flukes opposed to those of the next row ; 

 but sometimes 2 or 3 rows will point in one direction against -1 row opposing 

 them. All have nearly straight flukes, with no armature. Those at the 

 posterior end of body are not nearly so crowded. The plates are broad, shield- 

 shaped, with ca. 18-32 holes. The perforations in the handle are very 

 variable; sometimes 1 or 2 elongate perforations are present, and at other 

 times a large hole is surrounded, more or less regularly, with smaller holes. 



Distribution. — " Probably confined to the coasts of western and southern 

 Europe, and perhaps northern Africa " (Clark, 1907). 



Labidoplax Thomsoni (Herapath), 1865. 



Synapta digitata (partim) v. Marenzeller, 1893. 



„ thomsoni, Ludwig, 1898, and Ostergren, 1898. 

 Carrickfergas, Co. Antrim, type, Herapath, 1865. 



Clark (1907, p. 97) says :—" Although vouched for by such observers as 

 Herapath and Ludwig, the status of this species is not beyond question. 

 Marenzeller considered his specimens merely as a form of digitata." The 

 notes Under L. digitata of the Labidoplax specimens of our hauls show that 

 none possesses the assemblage of characters which are supposed to mark this 

 form, e.g., the absence of giant anchors, and the presence of a secondary net- 

 work on the plates, and the absence of sensory buds from the tentacles. 



I was unable to trace the type specimen, which is not preserved in the 

 museums of Dublin or Belfast. The form has been observed by Ludwig at 

 Naples, in Brittany by Barrels, and in the Adriatic by v. Marenzeller. 



