22 R. KIRKPATRICK. 



TRIBE ACICULIDA, Topsent. 



FAMILY STYLOCORDYLID^E, Topsent. 



STYLOCORDYLA BOREALIS var. acuata. 



(Plate XVI., figs. 6-10.) 



18G8. Hyalontma boreale Loven (Ofvers. Vetensk Akad. Forhand., Arg. xxv, No. 2, p. 105, pi. ii.). 

 1873. Stylocordyla borealis Wyville Thomson (' The Depths of the Sea,' p. 113, fig. 13). 



The small specimen representing this variety has a slender stalk 6 2 cm. long with 

 an oval head 7x5 mm. A second broken stem arises from the common base which 

 has a few grains of gravel and a fragment of the horny tube of a Hydroid attached 

 to it. 



The following spicular elements occur : 



1. Large oxeas with a central swelling (XVI. 10), in the axis of the stem, 

 1450 x 60/x. 



2. Smaller oxeas without central swelling (XVI. 8), in the radiating fibres of the 

 head, 900 x 20 p. 



3. Heteroxeas (XVI. 9) 1000 X 10 p. in the radiating fibres of the head. 



4. Microstyles (XVI. 7, 7a) 110 x 4 /*. vertically dressed at the surface of the 

 stem, and not found in the head. In the typical form there are microxeas, which 

 may be centrotylote. The variety is named " acuata " from the presence of the 

 microstyles. 



Topsent (25. p. 286) considered that Stylocordyla stipitata Carter, differs from 

 S. borealis in not having microxeas, which the latter possesses ; and he based his 

 opinion on the absence of these spicules from certain preparations of S. stipitata 

 lent to him by Canon Norman ; but I have found the microxeas in abundance in 

 Carter's type specimen. Accordingly there is probably only one known species of 

 Stylocordyla, viz., the typical S. borealis, and two varieties, var. globosa R. & D., and 

 var. acuata nov. 



The figures of Loven and Sars do not show any indication of the microxeas being 

 centro-tylote, but this condition is found in specimens from the Bay of Biscay. 



The Antarctic variety has no dermal tangential microscleres in the head, but 

 microxeas occur in this position in the typical forms from the North Atlantic. 



The ' Discovery ' dredged the specimen from off Erebus and Terror in 500 fms. 

 The species has been obtained from the following localities : 



North Sea (Loven) ; between Scotland and Faroe (Carter, Schulze) ; Grenada 

 (Schmidt); South of Nova Scotia, 85 fms. (Voy. 'Challenger'); Bay of Biscay, 1710 

 metres (Topsent) ; Bahia 7-20 fms. (Voy. ' Challenger ') ; var. globusa Southern Ocean 

 145 fms. (Voy. ' Challenger') ; off Kerguelen 10-100 fms., Voy. ' Challenger.' 



