* 



45 12 Proceedings of the Royal Irish Academy. 



This species is in some respects intermediate between the genera 

 Diosaccus and Amphiascus ; it is, however, quite distinct from 

 Scott's Pseudodiosaccus, which also exhibits characters of both genera. 

 The first pair of feet and the 1st and 2nd maxillipedes agree with 

 Diosaccus rather than Amphiascus, but the form and proportions of the 

 body and the form of the 2nd antenna are of the Amphiascus type. 



*A. cinctus (Cls.)— ? Westport Bay (B. & E.). Blacksod Bay, between tide- 

 marks, September, 1911, common. 



*&.. obscurus G-. 0. Sars. — Clew Bay, 18 fms., August, 1910, two. Blacksod 

 Bay, between tidemarks, March, 1911, two. These specimens do not agree 

 exactly with Sars' description and figures. They are distinctly larger, 

 ? l - 28 mm., $ 1*12 mm., and the female has only six setae on the second 

 joint of the 5th pair of feet, which thus resemble those of A. ductus. The 

 colour is the same as in Sars' specimens, the thoracic and abdominal 

 segments being of a dark reddish chocolate with the appendages and 

 caudal rami stained indigo. 



*A. similis Claus. — Ballynakill, 1901, 6-8 fms., one, 1-2 fms., one. Blacksod 

 Bay, between tidemarks, September, 1911, one. 

 A. phyllopus G. 0. Sars. — Blacksod Bay, 4 fms., September, 1910, one 2 . The 

 5th feet in this specimen are slightly wider than shown in Sars' figure, 

 approaching in form those of A. latifolius. 



*A. minutus Claus. — Inishlyre Boads, 2-4 fms., March, 1910, several. 



*A. longirostris Claus.— Clew Bay, 18 fms., August, 1910, two. 



*A. debilis G. O. Sars. — Ballynakill, 2 fms., 1901, one. 

 A. imus (Brady). — Clew Bay, in dredge (Brady, Mon.). 



*A. simulans ('Scott).— Off Killary Harbour, 24 fms., May, 1909, several. The 

 peculiar form of the first antennae, amongst other characters, distinguishes 

 this species from the allied A. sinuatus and A. spinulosus. 



"A. attenuatus G. O. Sars. — Off Killary Harbour, 24 fms., May, 1909, two. 

 A. hispidus (Brady).— Clew Bay, 10 fms. (Brady, Mon.). Ballynakill, 1901, 



one. 

 A. SPINIFER, n. sp. (PI. Ill, figs. 3-9).— Female (PL III, fig. 3), length 6 mm. 

 Body moderately slender, slightly tapered posteriorly. Eostrurn (Pl.1 1 1, 

 fig. 6) very long, more than half the length of the cephalic segment, 

 contracted towards the tip as in A. lagenirostris, but not so wide 

 basally as in that species. The 5th thoracic segment bears dorsally a 

 pair of large upward-directed spines, and the posterior dorsal margins of 

 the abdominal segments (PI. Ill, fig. 4) bear transverse rows of much 

 smaller spines, about eight spines in each row. Anal segment short, deeply 

 hollowed between the furcal rami, which are short, slightly longer than 



