43 



moderately long tentacles which curved gracefully so that each had somewhat the form of a 

 sickle, as in the D. armata figured by van Beneden (1898), although the additional length of 

 the tentacles in the present species made the curvature more distinct. In some of the smaller 

 individuals, indeed, the tentacles were spread out almost at right angles to the axis of the 

 column as is Solasteractis, but there was no distinct groove marking the.junction of their 

 aboral surfaces with the column wall. 



Dimensions. — Two distinct stages were represented in the collection. The examples 

 of the younger stage had a column length of about 1.25 mm. and the length of the marginal 

 tentacles varied from 1.0 to 2.0 mm. In the older individuals the length of the column varied 

 from 1.5 to 2.0 mm. and the length of the marginal tentacles was about 2.0 mm., although 

 in one example, owing to a greater contraction, they did not exceed 1 mm. 



Colouration. — No colour remained in any of the examples. 



Structure. — In the younger individuals there were seventeen marginal tentacles, 

 that is to say, eight couples and a median tentacle. The latter (PI. I, fig. 11) was indisting- 

 uishable by its length from the adjacent tentacles, while both members of the eighth couple 

 and the left member of the seventh couple were decidedly smaller than the others. Of the 

 labial tentacles there were six couples, the first couple corresponding to the second couple of 

 marginal tentacles and the others successively to the third, fourth, fifth, sixth and seventh 

 couples. No labial tentacles corresponding to the median or first couple of the marginals were 

 present, and, employing van Beneden's symbols the formula for the tentacles would be 



T K T 1 . TM. T 1 + T 8 



t 7 — t 2 t s — t 7 . 



The stomatodseum was rather deep, deepest in the region of the siphonoglyph and 

 diminishins: pradually thence toward the dorsal mid-line. Twenty ^^ 



mesenteries were present (Text-fig. XIII), an equal number on 

 either side of the mid-plane, although those of the right half of 

 the body were somewhat longer than those of the left half. The 

 directive mesenteries extended some distance below the lower 

 border of the siphonoglyph and were succeeded by two couples 

 provided with mesenterial filaments throughout only a portion of 

 their length. The fourth couple, on the other hand, were provided 

 with filaments throughout almost the whole length of their free 

 border and the filaments terminated in acontia. At this stage, it 

 is to be noted, these acontiferous mesenteries are shorter than 

 those of the second couple. To these protocnemic mesenteries 

 succeed six couples of deuterocnemes, gradually diminishing in 

 length, so that on the left side the last three mesenteries, and 

 on the right side the last two do not extend beyond the lower 



border of the stomatodseum. The other deuterocnemes, which do extend below the stomatodreum, 

 are provided with mesenterial filaments alternately straight and contorted, except on the left 



43 



Fig. XIII. 



Diagram showing the arrangement of 



the mesenteries and tentacles in a larva 



of Dactylactis malayensis. 



