118 AKT. 1. — I. ijiîiA : heXactinellida, iii. 



Postscript II. 



Following Schramm en's paper above referred to, I have 

 received, jiu-t in time to add this postscript, F. E. SniUEZE's 

 latest Hexactinellid work in which Caulophacus ardlcm (A. 

 Hansen) and Calycosoma gracile F. Fl Sch. nov. spec, are des- 

 cribed in detail (Abb. kgl. preuss. Akad. Wiss. 1903). 



With Caulophacus arclicus, which comes from a depth of 

 1977 m. in the Northeast Atlantic, a sixth species is added to 

 the five I have enumerated in this Contribution. As pointed out 

 by F. E. Schulze, it shows in the spiculation an extensive 

 agreement with, and therefore seems to be most closely related 

 to, C. latus of the South Indiau Ocean. So far as can be made 

 out with certainty from the descriptions and figures relating to 

 both, the following seem to be the most important features that 

 characterize C. arclicus as distinct from 0. latus : 1. The j^inular 

 ray of the dermalia is narrower and i)ointed at the apex, being 

 thus spindle-like instead of ovoid.'" 2. The slender pinular ray 

 of the gastralia is shorter by one-half or more, measuring 250- 

 500/^ in lenoth as ao-ainst 1mm. or more of G. latus. 3. The 

 occasional presence of hemihexactinose pachydiscohexasters in 

 addition to hexactinose forms.f 4. The tufts of terminals to 



* In the Cliall. Report (p. 125) the dermal pinular ray in C. InHis is stated lo be 

 usually 50 ij. long; but this scarcely accords with the size of its figure ns given /. c PI. 

 XXIV., fig. 10, magnified 100 times. One is led to suspect a typographical error or errors 

 in this connection ; but if it be that the scale of magnification^appended is correct, tlie 

 dermalia of C. Ia!us mu.st be said to have the pinular ray strikingly larger than that of 

 the same spicule in 'C. arclicus, — a fact which might conveniently be made use of as one 

 of the dißerential points between the two species. 



t F. E. Schulze (/. c. p. 8-11) disapproves of applying the term hexaster to the quasi- 

 hexactiu called by me tlie liexactinose hexaster. Grounds for my persisting to use tliis appella- 

 tion antl tlie advantage to be derived therefrom, will be dealt with in another jiublication. 



