REPORT ON THE ACTINTARIA. 93 



Willi smooth, with twelve longitudinal furrows, and numerous small openings at the 

 posterior end of the body ; twelve tentacles, each with an adaxial and an abaxial longi- 

 tudinal furrow ; six pairs of septa. 



Habitat. — Station 149. Off Kerguelen Islands, (a) January 9, 1874. Lat. 49° 16' S., 

 long. 70° 12' E. Betsy Cove. Depth, 25 fathoms. Two specimens, (b) January 

 29, 1874. Christmas Harbour. Depth, 120 fathoms. One specimen. 

 Dimensions.— Height, 1*5-2 cm. ; breadth, 0"5-l cm. 



The three specimens of Halcampa clavus which were sent me for examination varied 

 in size ; the two specimens taken in Betsy Cove were smaller than the one dredged up 

 in Christmas Harbour, and differed from it in habit of body. I believe, however, that 

 they should be referred to the same species, as the slight difference in size and form may 

 be the consequence of difference in age and degree of contraction, and their anatomical 

 constitution harmonizes completely. I examined the larger specimen, which was specially 

 well preserved, and one of the smaller ones. 



The body is divided by two circular constrictions into three sections lying one behind 

 the other. The middle section, the scapus — if we adopt the nomenclature proposed by 

 Gosse for Edwardsia — in the largest individual was rather longer than the other two 

 sections taken together, and about 1 cm. broad (PI. III. figs. 1 and 4); it passed anteriorly 

 into a short neck-like part bearing the tentacles, the capitulum, and posteriorly into a 

 terminal part, 0'5 cm. long and broad, the physa. A cuticular deposit, like that covering 

 the scapus of the Edwardsice, did not exist, but on the other hand the wall is regularly 

 divided by twelve longitudinal furrows, which begin at the upper end between the 

 twelve tentacles and reach as far as the lower umbilically depressed end. The 

 longitudinal furrows are crossed by numerous transverse furrows, which, however, may be 

 caused by the strong contraction of the animal. 



The wall is transparent and thin-membraned except at the points where the scapus 

 passes into the capitulum and the physa ; at the points mentioned it is greatly thickened 

 by increase of the supporting substance on the one hand and by numerous pleatings of 

 its endodermal and ectodermal surfaces on the other. The pleatings are caused by an 

 increase in the lamellse of the circular muscles, and may therefore be termed the upper and 

 lower sphincters, though they are by no means sharply defined. If we examine the wall 

 closely in longitudinal section we see that all over the inner side there is a layer of circular 

 fibres. The underlying supporting substance is divided into two layers, an inner, narrower, 

 nearly homogeneous layer, which stains a darker red in carmine, and an outer, broad, 

 fibrous layer, the two being separated by a sharp line. The inner layer is pleated at 

 tolerably regular intervals, into supporting folds, which run circularly, and project into 

 the gastric space ; they usually remain simple, and are rarely bifurcated at their 

 margins. Their surface is covered with numerous very fine, secondary folds, which 

 bear a layer of muscular fibrilla;, so that each circular fold appears finely pinnated 



