Mr. C. Spence Bate on the Affinity of Praniza with Anceus. 167 



The mandibles (d) originate from the inferior base of the 

 labium and project horizontally forwards, lying immediately 

 beneath and parallel with that organ ; the tips of the former ex- 

 tend beyond the extremity of the siphon. The anterior half of 

 the inner margin of each mandible is strongly denticulated. 



The maxilla {e, f) originate posteriorly to the mandibles, are 

 lanceolate in form, slightly curved, and serrated upon the inner 

 margin. 



The maxillipedes (g) consist of four or five articulations, from 

 the anterior inner margin of each of which a long lanceolate 

 process is produced. 



There is but a single pair of gnathopoda (h) ; these consist of 

 six articulations, — the coxa probably being fused, as is the case 

 with all the other limbs, into the body of the animal. The dac- 

 tylos of the gnathopoda is developed into a powerfully formed 

 hook, both the limbs being directed horizontally forwards. This 

 pair originates apparently from the ventral surface of the poste- 

 rior part of the cephalon ; but close observation, particularly in 

 a lateral aspect, discloses a small segment behind, and distinct 

 from the cephalon (PI. VI. fig. 8 H). It is from this segment that 

 the pair of gnathopoda originates. 



The two next pairs of legs are homologous with the two anterior 

 pairs of pereiopoda in Amphipoda. Each is laterally attached to 

 a distinct segment, and directed forwards. It is chiefly upon 

 this fact that Professor Dana has constituted his group Aniso- 

 poda. In this respect Anceus agrees with Praniza. 



The three posterior pairs of legs are the three posterior pereio- 

 poda, and are attached to one inflated membranous segment, the 

 result of a fusion of the three posterior segments of the pereion. 

 The pleon is much narrower than the pereion. It consists of 

 six distinct segments, each of which is furnished on each side 

 with a pair of ciliated foliaceous appendages attached to a uni- 

 articulate peduncle. The posterior segment terminates in a 

 point. 



This description is taken from Praniza cceruleata. It is to be 

 regretted that the name should have been adopted from the 

 colour of the animal. I have received them of a bright grass- 

 green from Mr. Loughrin of Polperro ; blue, from the crevices in 

 the slate in Plymouth Sound ; and dredged them of an ash-grey, 

 as well as transparent and a dirty-white, in five or six fathoms of 

 water in the same locality. There can be no doubt, moreover, 

 as stated by M. -Edwards, that P. fuscata of Johnston, which is 

 described to be of a reddish-brown colour, is the same animal. 



That we have more than one species is certain. Besides 

 c&ruleata, two specimens of a different species have been sent to 

 me by Mr. Edwards of Banff. This species, to the eye, differs in 



12* 



