REPORT ON THE HEXACTINELLIDA. 165 



Hexactinellids, the beautiful stalked form represented in PI. LXIII. fig. 1. The cup 

 measured 12 cm. in height, and as much in maximum breadth— at the circular superior 

 opening of the somewhat depressed and yet bell-shaped body. This form I have named 

 Crateromorpha murrayi in honour of my much esteemed friend John Murray. The 

 tubular stalk, which is broken oif inferiorly, has a parietal thickness of 3 mm., and a 

 diameter of 2'5 cm. Just beyond the trumpet-shaped expansion, where the stalk joins 

 the body, tlie latter exhibits a rounded boss-like protrusion (1*5 cm. in length), directed 

 outwards and upwards. The external surface of the body and of the stalk is smooth, and 

 covered by a fine quadrate lattice-work, through which numerous roundish incurrent 

 apertures are visible. The internal surface of the wide gastral cavity exhibits numerous 

 round excurrent apertures of the efferent system of canals, which are small in the 

 neighbourhood of the superior margin, but become gradually larger towards the base of 

 the cup, aud occur at last so close together, that a network of more or less slender septa 

 protrudes between them into the gastral cavity. 



The thickness of the body-wall is on an average between 2 to 3 cm. , and decreases 

 oradually upwards to the smooth sharp-edged margin, on which no distinct cuff-like 

 fringe was discoverable. 



Of the larger spicules of the parenchymal skeleton the most abundant are those 

 slender diact forms which are beset at both ends with small pointed spines. The ends are 

 thickened in club-shaped fashion, bluntly pointed, or less frequently simply rounded off. In 

 the middle these spicules are in some cases smooth, while in others they exhibit the familiar 

 annular swelling, or else four cruciate or two opposite hemispherical nodes. Beside these 

 we have to note the occurrence— characteristic of the species — of thick diacts of medium 

 length (2'5 to 4 cm.), which are curved in an Indian bow fashion, or else gently twisted 

 in the middle. They are here especially well developed, attaining a thickness of 0'15 mm., 

 and gradually decrease in diameter towards the extremities, where they end in blunt 

 points (PI. LXIII. fig. 4). The terminal portion may be smooth, as represented in 

 PI. LXIII. fig. 4, or laterally beset with numerous minute pointed spines. 



There is in the parenchyma a remarkably sparse occurrence of large or medium-sized 

 hexacts, an important item in distinguishing this species from the closely related Cratero- 

 morpha thierfelderi. 



Between the large parenchymalia there is an abundant occurrence of oxyhexasters 

 with short principal rays, and two to four long divergent terminals, which have either 

 a perfectly straight course, or are somewhat curved terminally (PI. LXIII. fig. 5). Less 

 frequently, and especially in the neighbourhood of the gastral surface, another form of 

 rosette is represented by small discohexasters, in which the somewhat short principal rays 

 bear on their terminal transverse discs numerous fine terminals, which vary in length, 

 and bear transversely on their extremities small convex toothed discs (PI. LXIII. 

 fig. 6). 



