964 PROF. J. p. McMURRICH OK 



structures of P. hasfMa (Haddon and Dixon, 1885) and P. tri- 

 capitata (Andres, 1883). 



There was no differentiation of the upper part of the column to 

 form a capitulum, nor was there any distinct margin. 



The tentacles are twelve in number, arranged in a single cycle. 

 They are of moderate length and stoutness, obtuse or tapering 

 slightly at the tips, but not capitate, and frequently with longi- 

 tudinal grooves. 



The lips are elevated considerably above the level of the 

 disk, and show only a single siphonoglyph (fig. 2), which is 

 completely separated from the rest of the stomatodpeum by the 

 fusion of its lips throughout the greater part of their extent. 

 At least this was the case in three individuals that I examined 

 anatomically, and it would seem, therefore, to be of general 

 occurrence. Sedgwick (1884) has described the same peculiarity 

 as occasional in P. hastata, but it is not mentioned by other 

 authors who have studied the anatomy of that species (Haddon, 

 1885, 1889 ; Faurot, 1890, 1895). 



The general surface of the stomatodfeum is longitudinally 

 grooved along the lines corresponding to the insertions of the 

 mesenteries, and each lip is raised in the intervals between the, 

 grooves into five rounded elevations, which correspond with the 

 intervals between the perfect mesenteries, with the exceptions of 

 those between the directives. One of these latter is quite small 

 and the other is repi-esented by the margins of the siphonoglyph, 

 which, although not elevated to any great extent beyond the rest 

 of the lips, nevertheless bear fine tuberculiform or digitiform 

 processes (figs. 2, 3) which correspond with the conchular lobes 

 of other forms. Two of these processes form a pair lying one 

 on either side of the more dorsal portion of the siphonoglyph 

 opening, and the three othei-s are situated more ventrally, the 

 median one being in the sagittal plane of the body, opposite 

 the bottom of the siphonoglyph. In three individuals examined, 

 of different sizes, I found no variation in the form or arrange- 

 ment of these conchular processes, and would therefore conclude 

 that this is their final adult arrangement. 



gi^p^^ — The height of the column, measured in individuals pre- 

 served in formalin, was in the larger forms about 2-0 cm., the 

 diameter at about the middle being about 0*9 cm., and at the 

 limbus 0'6 cm. The length of the tentacles was 0-4 cm. 



Colour. — Examples preserved in formalin retain a considerable 

 amount of the original coloration, and from these it is possible to 

 state that the general colour of the column is a moi'e or less 

 intense brownish red. In some cases it is distributed over the 

 entire extent of the column and in others it is limited to the 

 distal portion, the proximal or basal part being almost colourless. 

 A closer examination shows that the pigment is not uniformly 

 distributed throughout the area in which it occurs, but presents 

 the appearance of a brownish red ground-colour upon which 

 are scattered numerous minute dots of a paler shade, these 



