394 



Part TIL — Eighteenth Annual Report 



described species have been found either in shore pools or in comparatively 

 shallow water. The females do not appear to be very prolific ; they 

 usually carry but one ovisac, which contains only a few — frequently not 

 more than three or four — ova. It is interesting to note, however, that 

 though the creatures are small their ova are comparatively of large size. 



Leptopsyllus minor, which has not before been recorded from the Clyde, 

 was obtained in shore pools near Millport, Cumbrae, and also at Inverkip 

 during the past summer. 



Leptopsyllus herdmani, I. C. Thompson and A. Scott. 



1900. Leptopsyllus herdmani, I. C. Thomp. and A. Scott, 

 Trans. L'pool Biol. Soc, vol. xiv., p. 141, PI. VIII. 



A few specimens of this minute species were obtained, along with the 

 species just recorded, in the shore pools at Millport, Cumbrae, in May 

 1899. One of the principal differences between this species and 

 Leptopsyllus minor is in the comparative lengths of the inner and outer 

 branches of the first thoracic feet ; in the present form the inner branches 

 are considerably longer than the outer ones, while in Leptopsyllus minor 

 the inner are scarcely longer than the outer branches. There are some 

 other differences, but they are less obvious than the one referred to. 



Nannopus palustris, G. S. Brady. 



1878. Nannopus palustris, G. S. Brady, Mon. Brit Copep., 

 vol. ii., p. 101, PI. LXXVIL, figs. 18-20. 



This curious copepod was obtained in brackish-water pools at Inverkip, 

 Firth of Clyde, on May 13th, 1899, but it did not appear to be very 

 common. It has a superficial resemblance to Platychelipus, and may 

 have sometimes been passed over as such. There are very few Clyde 

 records for Nannopus. 



Cylindropsyllus minor, T. Scott. (PI. XIV., figs. 23-32.) 



1892. Cylindropsyllus minor, T. Scott, Part III., Tenth Ann. 

 Report Fish. Board for Scot, p. 260, PI. XI., figs. 17-24. 



The copepod described under this name was discovered in 1891 off St. 

 Monans, Firth of Forth. At that time no males had been observed, and 

 therefore, though the characters of the female, so far as they could be 

 made out, agreed very well with the definition of the genus Cylindrop- 

 syllus, there was still the probability that the species might not after all 

 be a true member of that genus. 



During the past year the examination of a gathering of entomostraca 

 collected in the same locality where the species was first discovered yielded 

 several additional specimens to those already observed, and this time both 

 males and females were obtained. The occurrence of these specimens has 

 enabled me not only to revise the previous description of the female, but 

 to add to that a description also of the male, and to show conclusively 

 that the species is a true Cylindropsyllus. 



Description of the Female. — Body cylindrical (fig. 23) ; length of the 

 specimen figured, 97mm. (fully of an inch). The antennules, which 

 are comparatively short, are nine-jointed; the second joint is considerably 

 longer than any of the other joints. Their proportional lengths are shown 

 approximately by the formula : — 



Proportional lengths of the joints, 7 • 43 • 14 • 10 • 10 • 8 • 16 

 Numbers of the joints, I • 2 ' 3 • 4 • 5 • 6 • ~7 



