278 Mr Shipley, On a new Parasite, etc. [Feb. 25, 



The most striking feature in which these parasites resemble 

 Echinorhynchus is in the structure of their skin and in the presence 

 of the extensions of the skin known as Lemnisci. The skin 

 consists of an outer fibrous layer, with no cell outlines. This 

 is pierced by numerous channels or spaces and is continuous with 

 two Lemnisci or processes hanging down in the body cavity. The 

 fluid which is found in the spaces of the skin can be withdrawn 

 into the Lemnisci. Within this layer is a muscular sheath. 



The body cavity contained numerous ova and aggregations of 

 small cells whose exact nature was not clear. There were traces 

 of ducts leading to the exterior at the posterior end. Although 

 owing to the state of preservation of the parasites, many details 

 could not be made out, the structure of the skin and the presence 

 of Lemnisci strongly support the view that we have in these 

 parasites animals which if they do not belong to the family of the 

 Echinorhynchidge are at any rate nearly allied to them. 



(3) Notes on Pachytheca (with exhibition of specimens). By 

 A. C. Seward, M.A. St John's College. 



The genus Pachytheca from Silurian and Devonian rocks of 

 Britain and Canada has been a subject of discussion among paleon- 

 tologists ever since its discovery in 1853. Several writers have 

 placed the fossil among algse, and this position has been assigned 

 to it on the grounds of a supposed resemblance of its histological 

 structures to that of certain recent genera. An examination of a 

 series of microscopic sections prepared by Mr Storrie of Cardiff 

 has led me to doubt the sufficiency of the evidence on which 

 the comparison with any existing alga has been based, and to regard 

 Pachytheca as an organism of uncertain position which might well 

 receive attention at the hands of zoologists. 



