1balf::*an^1bour at tbe flDicroacope^'^-^.J?^.^ 



Mttb /ll>i\ UwUcn Mest, ff.X.S., tf.1R,^.S., etc* 



Section of Spine of Echinus.— There are a large number of 

 species. To give this slide its true specific value, the locality 

 whence obtained should be named. With this drawback it 

 furnishes an admirable example of structure, the most complete 

 description of which was furnished by Dr. Carpenter to one of 

 the early meetings of the British Assocation, and will be found in 

 the Vol. of " Reports " for the year, along with the most exquisite 

 illustration (by W. S. Leonard) that has yet been given of it. 



Palate of Limpet. — It is a real treat to see this fine specimen 

 in its entirety. The lingual ribbon is, however, not coiled so 

 much as is here represented, and as the necessities of fitting to the 

 slip of glass require, but (speaking from memory) I believe the 

 coil is only about once round inside the shell. 



Pycnogonum. — I had been wishing that some representative of 

 these remarkable forms of life should be passed round, and here 

 is the unspoken wish gratified. R. H. M. will not be able to see 

 the contractile coeca after they have been removed by potash ; 

 they are indeed curious and interesting. 



Ammothea Pycnogoniodes. — G. Hodge, who has studied the 

 British Pycnogons more than anyone, and gives a list of all so far as 

 then known (Tyneside Trans., Vol. VI., Pt. 2, 1864, p. 198), only 

 enumerates two species of the genus — " A. drevipes," which this 

 appears to be, and " A. longipesy Prof. Allman has described a 

 similar parasitism on Coryne in this genus (Brit. Association 

 Reports, 1859). The number and character of the claws furnish 

 important aids in the discrimination of generic and specific 

 characters ; both the examples of Pycnogons in this box have 

 three ; one very large and strong, the other pair situated behind 

 and external to it, and more or less rudimentary. The parasitical 

 attachment of diatoms is curious and interesting. The species 

 are " Grammatophora fnarina " and " Cocconeis saitelhim,^^ the 

 latter sparingly ; also a Sy7iedra and a Biddulphia. Perhaps this 

 sort of thing may be more common than is at present supposed. 

 I found to my astonishment this summer a complete scale armour 

 of diatoms on some brackish-water larvae, mostly Cocco7ieis Flace?i- 

 tula. 



The mouth is suctorial in its character. It appears to consist 

 in this Ammothea of an upper and under lip, a pair of mandibles, 

 and a pair of maxillae, the whole together forming a tube ; a 

 central thick-walled pharynx, doubtless furnished with powerful 

 muscles and a beautiful structure at its base for facilitating con- 

 traction and expansion. 



Journal of Microscopy and Natural Science. 



New Series Vol. III. 1890. l 



