Clare Island Survey — Archiannelida and Pobjchaeta. 47 45 



Microphthalmia Sczelkowii Mecznikow. 

 PL V, figs. 6A-E. 1 

 1865. Microphthalmus Sczelkowii. Mecznikow, p, 334, taf. xxiv, figs. 10-12. 

 Three specimens of this species were found under stones on the shores of 

 Blacksod Bay. Eeproductive elements were not present in any of them. 



The largest specimen is 6 mm. long, composed of 40 setigerous segments. 

 The other two are smaller, 2'2 mm. and 2 - 8 mm. long, with 23 and 25 

 setigerous segments respectively. 



The body is widest in the anterior third, tapering slightly towards the head, 

 considerably towards the tail. The lateral regions are flattened, leaving a 

 prominent dorsal ridge, from the front of which rises the median antenna 

 (PI. V, fig. 6a). This dorsal ridge may be the result of contraction. There is 

 considerable brown pigment on the dorsum, especially in the lateral region, 

 forming four ill-defined transverse bands in each segment. 



The head (PL V, fig. 6a) is rounded in front, where it is slightly indented. 

 The posterior margin is rounded at the sides, and concave in the middle. In 

 the posterior region of the head is a single pair of small black kidney-shaped 

 eyes, without lenses. In front of the head are four slender tapering tentacles, 

 the dorsal pair slightly longer than the ventral pair, all without basal 

 articulation. In the posterior indentation of the head rises the median 

 tentacle, which equals the dorsal tentacles in length. 



There are three pairs of tentacular cirri on each side. The segments 

 bearing them are distinct from each other, and from the head. The tenta- 

 cular cirri are somewhat swollen in the basal portion, tapering distally. The 

 anterior pair are almost equal in size, and are shorter than the second pair, 

 which again are almost equal. The dorsal cirrus of the third segment is the 

 longest appendage of the body, and is twice as long as the ventral one. The 

 feet are all similar in structure, and the fourteenth may be described as 

 typical (PL V, fig. 6d). The dorsal cirrus is broad at the base, tapering to a fine 

 tip, and is twice as long as the ventral cirrus. The dorsal division of the 

 foot is rudimentary, consisting of a slender spine, and a single small seta 

 with a peculiar spinous tip (PL V, fig. 6e, a). The ventral division of the foot 

 is prominent, with a single large spine, and a fan-shaped series of about 10 

 setae. The setae in the middle of the foot have the longest tips, those in the 

 ventral region the shortest, whilst the dorsal setae are intermediate. The 

 shafts of the setae are gently curved, with bevelled, slightly bind tips (PL V, 

 fig. 6e, b, c). The terminal pieces are minutely serrate, bifid at the tip. Beneath 

 the lower tooth is a long slender tooth parallel to the tip. 



1 The figures for this species and for Opisthodonta plerochacla , which hy error have both been 

 numbered 6, may bo distinguished by the number of the plate. 



