108 PROCEEDINGS OF THE 



same stem bearing one only. This latter fact would lead us to 

 adopt, instead of the theory of the bifiurcation of the fruit rudi- 

 ment, rather that which supposes the cause of the abnormality to 

 lie in the archegonium itself. But in the absence of the calyptra, 

 as in the j^resent case, it would be impossible to say whether such 

 an abnormality was the production of two germinal vesicles in one 

 and the same archegonium, or of twin archegonia. If there were 

 but one calyptra covering both capsules, the former probability 

 might be assumed, while if each of the twin capsules was provided 

 with a perfect calyptra, we might reasonably believe them to have 

 been produced from twin archegonia. 



Referring to the specimen of Atrichum unclulatnm with the 

 calyptra attached to the seta, Mr M'Kinlay observed that the 

 calyptra not unfrequently takes up that anomalous position, 

 especially in young plants of this species. In such cases, also, 

 owing, no doubt, to the want of the protection afforded by the 

 calyptra to the growing point, the capsule itself seems invariably 

 to be al)normal in shajDe — short and ovate as in Atrichum tenellum, 

 and with a much shorter lid than usual. 



Mr M'Kinlay likewise exhibited specimens of a rare and little 

 known moss — Campylopns densus (Schleicher), gathered by himself 

 on Ben Challum in September, 1863, and again, in company mtli 

 Mr Shaw, on the island of Unst, Shetland, in great profusion, in 

 June last. This species has not hitherto been recorded as a 

 native of Britain.* 



Mr David Robertson exhibited, from Cumbrae, an entomos- 

 tracan of the genus Longijiedia, recently named by Claus, and read 

 the following remarks: — This little entomostracan, taken at Cum- 

 brae, is new to Britain. It belongs to a new genus, Longipedia, 

 constituted by Dr Claus in his work recently published on 

 the "Copepoda of Germany, the North Sea, and the Medi- 

 terranean." 



In this genus he has but one species, L. coronata, but whether this 

 one from Cumbrae is identical, I am not quite sure, there being- 

 some slight difference of structure between them. Claus' figure is 



* The specimens exhibited were afterwards found to be the same as C. 

 compactus, Schpr., which was not then published. It has since been found in 

 very many places in the Highlands of Scotland. C. densus, which was at this 

 time believed to be a distinct species (Schimper's Synopsis, 1860, p. 99), is now 

 united with C. frayilk. — A. IM'K. 



