HALICREAS PAPILLOSUM. 



139 



Station 4715; 300 fathoms to surface ; 1 fragmentary specimen. 



Station 4716 ; 800 fathoms to surface ; 1 good specimen. 



Station 4717 ; 300 fathoms to surface ; 1 good, and 1 fair specimen. 



Station 4717; in trawl from 2,153 fathoms; 1 fair specimen. 



Station 4719 ; 300 fathoms to surface; fragments. 



Station 4721 ; 300 fathoms to surface ; fragments. 



Station 4724 ; in trawl from 1,841 fathoms ; fragments. 



The numbers of tentacles and otocysts per octant, and the conformation 

 of the apical projection, in the five best-preserved specimens are shown in 

 the following table : — 



The form of the apical projection varies greatly, all stages being repre- 

 sented in the collection, from a very tall pyramid to an inconspicuous knob ; 

 and one specimen shows no trace of any projection. This feature, then, as 

 Maas has already surmised (: 05, p. 56), is not of specific significance. The 

 bell is stiff and the gelatinous substance thick, as described by all students 

 ■who have examined the species. 



The eight peculiar radial gelatinous projections of the exumbrella are 

 represented in the photographs (PI. 34, figs. 1 and 3, p. ra). Each prom- 

 inence bears from five to nine rounded conical projections (PI. 34, fig. 5); 

 the whole forming a structure totally unlike anything seen in any other 

 Medusa. They are much more prominent in large than in small individuals. 

 The portion of the bell below the level of the prominences is thin and flex- 

 ible, sharply defined from the stiff gelatinous disc above. When, as is often 

 the case, the entodermic system is torn away, a very definite sculpture of 

 the oral surface of the disc, consisting of a ridge along the line of each radial 

 canal and of a rounded prominence between the bases of every two canals, 

 is revealed (Vanhoffen, : 02**, p. 69). 



Tentacles. — The number of tentacles per octant is variable, as appears 

 from the preceding table. The largest number observed in any octant was 



