60 PORIFERA. III. 



same length as the tooth. The length is 0-035 0-044"', the shaft is flattened, its thickness is in 

 relation to this 0-003 '7 """ The c ^^ x occur through the whole sponge and in a dense layer in 

 the dermal membrane. 



This species is somewhat characteristic, besides from its exterior, from the small acanthostyli 

 being straight and slender and with large, distinctly reclined spines, and from the large strongyla; it is 

 to be noted that it is not the smallest styli, but those a little longer which especially have large 

 spines. The species is nearly related to the preceding H. stylata, but it is distinguished by the small 

 acanthostyli with their large, reclined spines and distinct heads; also the strongyla are different, and 

 the alse of the chelae are longer and more pointed in H. stylala. 



Locality: Station 54, 63 08' Lat N., 15 40' Long. W., depth 691 fathoms; and at 64 42' I/at N., 

 27 43' Long. W., depth 426 fathoms (Wandel). In all four specimens. The localities lie in the Den- 

 mark Strait and south of Iceland. 



15. H. procumbens n. sp. 

 PI. VII, Fig. 2. 



Incrusting; surface slightly hispid. Spicula: megasclcra; the skeletal spicules acanthostyli with 

 a small head, spincd in the whole or nearly the whole length, the longer only very slightly spincd otit- 

 wards, 0-089 '35 mm > n t divided into two distinct groups ; the dermal spicules tornota (j-2jo-j2?"""; 

 microsclera chela arcuatce, often strongly curved, 0-024 o-oj6'""". 



This species grows as small incrustations on pebbles, one specimen grows on the shell of 

 an Area, and one on a dead Oculina; it has a greatest extent of about 12 mm , and the thickness 

 is exceedingly small. The colour (in spirit) is nearest whitish or whitish grey. The surface is 

 very slightly hispid on account of the generally only to a slight degree projecting spicules. The 

 dermal membrane is a thin film, supported by bundles of dermal spicules; it has somewhat densely 

 lying chelse. 



The skeleton. The dermal skeleton consists of bundles of dermal spicules which are generally 

 somewhat fan-like spread; the bundles stretch out to the surface, but they are for the greatest part 

 strongly decumbent in the membrane. The main skeleton has the typical construction; it is rather 

 dispersed, the single styli standing somewhat scattered. Spongin I could not observe. 



Spicula: a. Megasclcra. i. The skeletal spicules are straight or nearly straight acanthostyli 

 with the head-end most frequently rather weakly marked ; the longest styli are often somewhat curved 

 near the base; the spines are large on the head-end, but decrease rapidly outwards both with regard 

 to size and to number, and the largest styli have thus the spines on the outer part much dispersed, 

 and the spines are here weak. The small styli are entirely spined, and the spines are larger, but 

 there does not seem to be sharply divided groups. The length is 0-089 0-35 mm an< ^ the diameter of 

 the head is o-oi 1 0-027""". 2 - The dermal spicules are tornota which are straight, or sometimes a 

 little irregularly curved; one end is generally slightly thinner than the other; they are fusiform, being 

 somewhat thicker in the middle, and some few are seen reaching a considerable thickness. The 

 length varies much, from 0-23 0-327 nim , and the diameter is 0-004 0-0075 mm . b. Microsclera; these are 



