HARMOTHOE IMBRICATA. 323 



those of Lepidonotus squamatus (Plate XXVI a, fig. 2). When punctured the tissues of 

 a ripe male heal in a day or two, and the animal regains activity. 



In the first week of March the trochophores swarmed in the vessels containing the 

 adults, congregating like the copepods and Nauplii at the margin next the light. The 

 early trochophores (Fig. 29) present a less developed ring of cilia, but soon (Fig. 30) 



Fig. 29. Fig. 30. 



FlG. 29. — Early trocliopliore of Harmothoe imbricata viewed from the anterior end. 



Fig. 30. — Trocliopliore of Harmothoe imbricata with fully developed pre-oral ring of longer cilia in rapid movement, 



viewed as in Fig. 29, from above. 



these organs assume a characteristic appearance, and the larvse are very active. They 

 are bluntly conical at both ends, and devoid of eyes. When compressed under a cover 

 the ring of cilia (pre-oral) (Plate XXVI A, fig. 3) has a very regular rotular aspect. 

 Those captured by the bottom tow-net in the Bay at this time were somewhat larger. 



On the 28th March the larvae in confinement had for the most part gone to the 

 bottom, and, moreover, had assumed a greenish appearance, as indicated in the figure. 

 In the same plate (XXVI a) the older trochophores with a pair of eyes are shown in 

 various positions in figs. 4, 5, and 6. In the first-mentioned figure the mouth forms a 

 projection to the left. 



On the 25th April the intermediate stages occur in the bottom tow-nets, viz. larger 

 and more advanced forms having a bluntly rounded anterior end, a prominent ventral 

 surface, and minute feet, with or without traces of bristles, the feet being marked only by 

 crenations. The head is bluntly rounded, with two or three pairs of eyes, and the body 

 is somewhat pear-shaped (Plate XXVI a, fig. 7). The digestive apparatus is indicated by 

 the opaque granules in front and the paler posterior region. 



Very soon (indeed, in the nets of the same date) the bristles make their appearance in 

 the feet (Plate XXVI a, figs. 8 and 9), though the head still remains blunt. In the first- 

 mentioned figure the foot-papillaa are minute, and project very little in lateral view, but 

 as transparent objects they show traces of the bristles. The latter project by degrees 

 from the ventral division of the foot, and present a somewhat broad spinous tip with 

 distinct spinous rows and a well-marked terminal hook, but no secondary process. 

 When they become more elongated, so that the shaft is clear for a considerable distance, 

 a trace of a secondary process occurs below the hooked tip. Minute scales have also 

 made their appearance. No anal papilla (cirri) are yet visible, though in front the 

 tentacular cirri are represented by papillae. A line of pigment occurs at the ciliated 

 ring, and the eyes present a rudimentary lens. 



