290 "TERRA NOVA' EXPEDITION. 



from further recorded localities ; and Professor Chilton kindly placed all his material 

 at my disposal. It is, therefore, possible for me to add to this report a description 

 of T. novae-zealandiae, and to make my account of the whole genus complete by including 

 a description of T. tenuipes as well. 



In 1918 I gave a new definition of the genus, which, however, now requires modifica- 

 tion in one or two points. In one of the new species described below, only the last 

 thoracic somite is left exposed by the carapace, and the endopod of the fourth pair 

 of pleopods in the male may have only one instead of two modified setae. With these 

 emendations the diagnosis given in 1918 may be allowed to stand. The genus, so 

 far as at present larown, is pecuUar to New Zealand, where, however, it appears to be 

 very abundant and widespread. 



A key to the nine species of the genus follows, and may be useful for the quick 

 determination of species. Two main groups of species can be distinguished, one in 

 which the antero-lateral angles of the carapace are produced into acute spines and 

 the other in which they are rounded. 



Key to the known species of the Genus TENAGOMYSIS. 



A. Antero-lateral angles of the carapace produced into acute spines. 



(1) Antennal scale about twice as long as the antennular peduncle. 



(a) Rostrum rounded ; antennal scale five times as long as broad ; telson with 12-14 

 spines on the lateral margins. T. novae-zealandiae, G. M. Thomson. 



(6) Rostrum obtuse with a blunt apex ; antero-lateral angles of the carapace set back ; 

 a prominent spine on the body of the mandibles external to the attachment of the palps ; 

 antennal scale ten times as long as broad ; telson with 16-18 spines on the lateral 

 margins. T. chiltoni, sp. nov. 



(2) Antennal scale barely extending beyond or even only equal in length to the antennular 



peduncle. 



(a) Rostrum sub-acute ; eyes short and normal in shape ; antennal scale three and a 

 half times as long as broad ; telson with nine spines on the lateral margins. 



T. similis, sp. nov. 

 (6) Rostrum evenly rounded ; eyes long and narrow ; antennal scale six times as long 

 as broad ; telson with 12-14 spines on the lateral margins. T. macropsis, sp. nov. 

 B. Antero-lateral angles of the carapace rounded. 



(1) Inner and outer uropods subequal in length. 



Rostrum small, obtuse ; eyes moderately large and normal in form ; antennal scale four 

 times as long as broad ; antennular peduncle equal in length to the antennal, both 

 robust in form ; telson with 18-20 spines on the lateral margins ; tarsus of the thoracic 

 legs composed of two to three joints. T. rohusta, sp. nov. 



(2) Outer uropod considerably longer than the inner uropod. 



(«) Antennal scale equal in length to the antennular peduncle ; rostrum short and obtuse ; 



eyes small and normal ; antennal scale eight times as long as broad ; last joint of the 



antennular joeduncle almost as long as the first ; telson with 26-28 spines on the 



lateral margins ; generally a slender species. T. tliomsoni, sp. nov. 



(6) Antennal scale at least one quarter longer than the antennular peduncle. 



(i) Rostrum greatly elongated in the form of a triangular plate with an acutely pointed 

 apex, extending to the distal end of the first joint of the antennular peduncle. 

 Eyes normal in shajje ; antennal scale six and a half times as long as broad, with 

 an acutely pointed apex ; telson with 26 spines on each margin. 



T. prodticta, sp. nov. 



