276 DISCOVERY REPORTS 



appear to live on a fine weedi which is uniformly spread over the bottom of the harbour 

 in Whale Sound. There is no mud in this region, only fine sand. The gonozooids are 

 always on the move, crawling in and out the fine filaments and twisting themselves into 

 the most peculiar shapes as they slowly progress through the miniature tangled forest." 



This new collection consists of eighteen specimens, preserved in 90% alcohol. 

 Some few specimens are well preserved, but most of them are more or less damaged and 

 have lost several or all of their tentacles. They were found in about the same locality 

 and at the same season as the type specimen, but on another species of alga. In the 

 structure of the tentacles they diflFer slightly from the type. 



A re-examination of the type specimen shows that the original description and 

 drawings are correct in every detail. In the type the lower branch of the tentacles with 

 the adhesive disk is only slightly longer than the upper branch with the clusters of 

 nematocysts. In the specimens obtained in 1901 the diflterence in length of the two 

 branches is almost always considerably larger. This may to some extent be due to 

 different states of contraction ; but even in tentacles, in which the upper branch seems 

 to be extended to about the same degree as in the type, the lower branch is usually 

 twice, sometimes even three times, as long as the upper branch ; in a few specimens, 

 however, the two branches differ only very slightly in length. The relative length of 

 the branches therefore seems to be subject to some variation independent of the state 

 of contraction. 



In the type a cluster of nematocysts is occasionally present on the lower side of the 

 upper branch of the tentacles, but in most of the tentacles nematocyst clusters are only 

 found on the upper side, one to three in number (exclusive of the terminal cluster). In 

 the specimens taken in 1901 the lower side is always provided with clusters of nemato- 

 cysts, except in very young tentacles with only one cluster on the upper side. In fully 

 developed tentacles the usual number is three on the upper side and two on the lower 

 side, alternately placed. Sometimes a third very small cluster is observed on the lower 

 side, and in a few tentacles a fourth cluster is added on the upper side of the branch, 

 close to its base (Plate XIX, fig. 2). According to the stage of development of the tentacle 

 the number of nematocyst clusters (excluding the terminal one) are: i/o, i/i, 2/1, 2/2, 

 3/2, 3/3, 4/3. In one exception the number was 3/1, but 2/0 or 3/0 has not been observed 

 in any of these specimens, whereas it is the rule in the type specimen. For comparison 

 with other species of Staurocladia it should be emphasized that the position of the 

 nematocyst clusters is decidedly median (on the upper and lower side) without the 

 slightest indication of a lateral position. Each cluster of nematocysts is crescent-shaped, 

 thick in the middle, tapering towards both sides, clasping around about one-third of the 

 circumference of the tentacle when fully developed; young clusters are circular in 

 outline ; the terminal cluster is spherical. 



Remarks on the specimens, (i) Diameter of the umbrella 1-45 mm., tentacles 

 1-45 mm. long, number of tentacles about twenty-four. (2) Diameter 1-35 mm., 



1 Sphacelaria sp., kindly identified by Dr H. E. Petersen, Copenhagen. 



