270 " ENDEAVOUR " SCIENTIFIC RESULTS. 



? Sertularia crinoidea, Allman, Journ. Linn. Soc, Zool., xix., 

 1885, p. 141, pi. xvi., figs. 1-2. 



S. minima is the best-known representative of a small 

 group of species — comprising also S. minuta, S. muelleri, and 

 S. pusilla — which agree in the simple habit, the bidentate 

 hydrothecse, and the squat high-shouldered compressed 

 gonothecse ; and which also agree, as pointed out by Mulder 

 and Trebilcock in a recent paper (cited above), in the presence 

 near the base of the internodes of small circular orifices, 

 generally associated with delicate tubular appendages pro- 

 jecting externally, and described as resembling rudimentary 

 sarcothecse. 



In the type form the hydrorhiza has the transverse 

 markings along the edges, consisting of perisarcal thickenings, 

 which are familiar to observers as occurring in many small 

 Sertularians and Plumularians, but in some forms these are 

 wanting. In typical specimens from Port Phillip, Victoria, 

 I find very few of the orifices above referred to ; on some 

 shoots none were present, on others I found one only, 

 situated at or close to the base of the first internode. The 

 lower internodes are commonly rather broader at the base 

 than the rest, tending towards a rectangular form, and the 

 orifices are mostly just at the angle. The tubules are quite 

 rudimentary, consisting of an extremely narrow projecting 

 rim. A New Zealand specimen is very similar, but the 

 orifices are found here and there on other internodes than 

 the proximal ones ; the little receptacles are somewhat more 

 developed, and are tubular or slightly expanding. 



The variety formerly described as S. pumiloides is larger 

 in all its parts, both in the trophosome and the gonangia. 

 Its hydrorhiza may be a simple filiform tube, or, as in a 

 specimen from Queenscliff, Victoria, may have a series of 

 lateral contractions, so that it appears scalloped along both 

 margins. The little tubes are as in the last-mentioned form, 

 and rare except on the proximal internodes. 



Another form, which we may call var. intermedia, links 

 the present species with *S'. minuta. Its internodes are 

 compact and square at the base, and the hydrothecse have 

 a decided constriction and oblique fold on the outer side, a 

 little above the base. These characters are very commonly 

 found in the proximal internodes of the type form ; here, 

 however, they are more pronounced and extend throughout. 

 The tubules are well-developed, slightly expanding, projecting 

 from the lower angles, and, as in S. minuta, they occur on 

 both sides and on all or nearly all the internodes. The 

 hydrorhiza is typical. 



