7« 



PORIFERA. III. 



appeared to be somewhat transformed by the preservation in alcohol, but the whole sponge is also 

 evidently highly influenced by the alcohol, the surface being wrinkled to a high degree. I am 

 inclined to think that the exceedingly thin sponge is somewhat mucous in the fresh state, and then 

 is highly contracted by the influence of the alcohol, and this would fully explain the remarkable 

 condition seen in the skeleton. 



Spicula: a. Megasclcra. i. The skeletal spicules are acanthostyli of a very characteristic 

 shape; they are short and straight, slightly tapering towards the point, this latter is broadly truncate, 

 so that the spicule is nearly cylindrical; they are strongly spined in the whole length, only a little 

 above the base there is an unspiued part, and this part is also a little thinner than the rest of the 

 spicule, thus forming a characteristic, neck-shaped constriction; though there is no real head- 

 swelling, the shape mentioned gives the base of the spicule the appearance of a head. Only very 

 rarely the neck-formed constriction is less obvious. The length of the acanthostyli is very uniform, 

 0065— 0-077 n,m , an( ^ tne diameter at the base is 0017 — 0-024 mm . 2 - The dermal spicules are tylota; 

 the}' are straight and rather robust, and they are of the same or nearly the same thickness in the 

 whole length, but just before the ends they are somewhat narrowed, and this narrowing gives rise to 

 the rather slight end-swellings. The shaft is often slightly polytylote. The length is 0-28— 0-369 ram , 

 and the diameter 0-009— o-oi2 mm . h. Microsclera ; these are chelae arcuatse; they have a curved shaft, 

 the teeth are so directed that they are lying in a straight line drawn between the ends of the 

 chela; the alae are somewhat narrow and rather incised in the lower margin when seen in front view; 

 the tooth is narrowly elliptical. The chelae are small, the length is 0-021— 0-023 mn ' and the thickness 

 of the shaft about 00028 mm . Not rarely chelae occur which are thicker and more robust in all parts, 

 but these give the impression of not being quite normal. The chelae are seen in the dermal mem- 

 brane and in the other parts of the sponge, but generally not in great numbers, on the other hand 

 they are very numerous on the oscular papillae. 



This species is nearly related to H. Bowerbanki, but it is easily distinguished by the characteristic 

 acanthostyli as also by several other more minute characters. 



Locality: Station 85, 63°2i'Lat. N., 25°2i' Long.W., depth 170 fathoms; station 89, 64° 45' L,at. N., 

 27 20' Long. W., depth 310 fathoms; further it has been taken in Forsblads Fjord in Kast Greenland, 

 depth 50—90 fathoms (The East Greenland Expedition 1900), at 66° 54' L,at. N., 15 38' Long. W., depth 

 58 fathoms ("Beskytteren"), South-west of Sudero, depth 180 fathoms (Ad. Jensen, the cruise of "M. Sars" 

 1902). The localities are situated on the East coast of Greenland, in the Denmark Strait, North of 

 Iceland and at the Faroe Islands. 



29. H. latrunculioides u. sp. 

 PI. Ill, Fig. io, PI. VIII, Fig. 7. 

 Incrusting; surface smooth, bearing some oscular papilla: wit// a dense skeleton of dermal spicules 

 in the wall. Spicula: megasclera; the skeletal spicules short, conical, very strongly spined acanthostyli 

 with a neck-shaped constriction above the base; they are oj one size 0-065 — o-oji""" ; the dermal spicules 

 tylota, but often with such small swellings, that they approach nearly to strongyla, o-jo — o-jo""": micro- 

 sclera chela arcuatm 0-023— 0-028""". 



