ROBSON— ON THE CEPHALOPODA 441 



dorsally, probably by the action of the preserving agent, and exhibits a sparse array of 

 papillfe some of which are multifid. There are a few papillse round each eye. 



The arms exhibit the formula 2 = 3 = 4.1. There is a weakly developed umhrellar 

 membrane extending a few millimetres up each arm. 



The colouring is a brownish purple on the back, passing to a very pale yellowish 

 brown ventrally, the whole. covered with numerous black chromatophores. Very charac- 

 teristic is an oval patch of an intense blue-black colour, about 2 mm. long, situated on 

 either side somewhat posterior to the eye at the base of the third arm. Such patches are 

 found in this position in P. horsti (Joubin (12)), but although this is a common character- 

 istic between the two species, the radulse, as well as other structures, differ too widely 

 to allow of uniting the two forms (of. Plate 66, fig. 4 a and Text-fig. of Hoyle (G)). 



Radula (cf. fig. 4 a). 



Internal anatomy. The heart is relatively very large and is markedly rounded ; the 

 efferent vessels enter it at equal distances from the anterior aorta. The auricles lie very 

 near the surface in close proximity to the renal aperture. 



The ovary, in accordance with the immature age of the specimen, is very small, 

 much smaller in fact than the capsule. The oviducal glands are also very small and the 

 oviducts long and slender. These open low down in the mantle cavity towards the median 

 line in the region of the kidney. 



Indeterminate juvenile examples. 



A single very small example from "6. 10. 05," 140 fathoms (1538). The only salient 

 characters are its squat build and the plentiful scattering of brownish-black chromatophores 

 all over the mantle. 



A single juvenile example from Providence, 39 fathoms (1408). Possibly young form 

 of P. granulatus. 



^^ 



