248 Transactions. — Zoology. 



Upper side, various spines, chiefly arranged in 



two longitudinal rows. 

 Under side, spines chiefly arranged in two 



longitudinal rows ; strong spines in the 



centre. 



The fingers end in strong incurved spines, inner margins 

 with three or four rounded prominences. The propodos (with- 

 out the fixed finger) is one and a half times as long as the 

 carpus, and about twdce as long as broad. The pleura of 

 the abdominal segments is quite rounded below, and has 

 setae both on anterior and posterior margins. (See Plate X., 

 fig. 2a.) 



All the parts I have thus described are subject to much 

 variation, as in P. planifrons, and I need not go over each in 

 detail, but only mention those in which this species sometimes 

 differs from P . planifrons . The bulging of the branchiostegites 

 is only found in the specimens from the Avon and Heath- 

 cote ; the others have the sides straight as in P. planifrons. 

 The epistoma is often narrow, but is sometimes broad, flat, 

 and triangular, as in P . planifrons . The spines on the sides of 

 the carapace vary very greatly : in large specimens, especially 

 those from the Avon and Heathcote, they are very numerous 

 and prominent ; but in others, from Rangiora and Dunedin, 

 only a few are represented, and the greater part is quite 

 smooth. Some of these specimens would correspond fairly well 

 with the description of P. zealandicus, White, as given in Miers's 

 catalogue. The relative lengths of the joints of the great 

 claws vary a good deal, as in P . planifrons ; but these limbs 

 are usually shorter and broader than in that species. The 

 pleura of the abdominal segments often have the infero-pos- 

 terior angle more pointed than in the Avon specimens, thus 

 approaching P. planifrons. The large specimen in the Otago 

 Museum, labelled P. sctosus in Professor Button's hand- 

 writing, is the largest I have seen, being 6-3in. long ; the sides 

 of the branchiostegites are quite straight ; the spines on the 

 carapace, though numerous and well marked, are all rounded 

 at the end, so as to be almost tuberculiform ; the propodos of 

 the great claws is very little compressed, and somewhat re- 

 sembles that of P. planifrons, though stouter ; and the upper 

 margin bears very few spines, the tufts of hairs arising out of 

 small tubercles instead. 



In both species the females, especially when bearing eggs, 

 have the abdomen wider than it is in the male, but beyond 

 tliis I have noticed no other differences between the sexes. 



I append brief diagnoses of the two species, with the 

 synonymy so far as it is known to me. 



