THE OSTEACODA. 233 



described and figured (xxx. 3) by Miiller ; it was not observed to show so much variation 

 as at Stage I. ; this may be accidental, as a good deal was observed at ? Stage III. below 

 (0"5 mm.). Antenna ii. as in Stage I. 



Earlier Stages. 



Male (about 0'5 mm.). — Shell markedly resembling that of the female at the same 

 length ; posterior border rather straight ; a steady curve from the gland-opening to 

 just below the rostrum, not flattened antero-ventrally. Frontal organ unsegmented, 

 nearly straight, sometimes tapered, ending bluntly. Antenna i. with principal bristle 

 of female character. Antenna ii. carries one basal bristle (?two), and two central 

 bristles as before. 



Pemale (about 0-5 mm.). — Shell higher for its length than in the later stages, 

 posterior border nearly straight, followed by a strong arching of the ventral border. 

 Prontal organ exhibiting similar variation to Stage I. ; the commonest type is shown 

 in fig. 51. Antenna ii. as in later stages. 



Figures are also given of (? ? ) shells at 0*45 and 039 mm., which may perhaps 

 illustrate earlier stages. 



CONCHCECIA DAPHNOIDES, Claus. 



(Plate 17. figs. 55-57.) 



Both males and females at Stage I. were fairly numerous. I have no doubt that what 

 has been described as lacerta, Brady & Norman, and daphnoides, var. minor, Miiller, 

 form Stage II. of this species *, but it was not taken by the ' Research ' on this occasion. 

 A single specimen of Stage III. was, however, captured. 



In supplement to Miiller's description, it may be noted that in the male nine reversed 

 teeth were counted at the distal end of the armature of the principal bristle, and that the 

 proximal bristle carried a few fairly stout teeth. In the female, the inner branch of 

 antenna ii. resembled Miiller's figure of the male (xxxi. 13), except, of course, for the 

 absence of the hook, and sometimes carried one basal bristle; the three sense-tubes were 

 spined proximally, the two bristles distally. 



The shells and frontal organ of Stage III. are figured. In antenna ii. the central 

 bristles were as in Stage I., but hairless ; there was no basal bristle ; the terminal 

 bristles and tubes were spineless. 



CONCHCECIA ELEGANS, SarS. 



(Plates 17, 18. figs. 58-73.) 

 Stage II. 



Male (Mean, ill)- — Shell without marked shoulder-ridge (unlike sp/w/ros^Ws); 

 generally with two sliarp spines on the postero-dorsal angle of the right shell ; below 

 the spines the posterior border is concave for a short distance, then convex. The 

 opening of the right asymmetrical gland does not project as in procera ; it lies at the 

 postero-ventral angle of the shell, not far forward as in procera ; the angle is well- 

 marked as the meeting-point of the posterior and ventral borders, unlike splnifera. 



* Compare p. 263 note. 



