260 Dr. J.Young on the Malacostraca of Aristotle. 



specially mark Cancer Bernhardus, the larger left pincer being 

 equally distinctive of Diogenes varians. Their anatomy is very 

 briefly stated. The interior of the soft body is pale : they have 

 an oesophagus terminating in a stomach ; but the vent is not 

 evident : no hint as to the direction of a gut. They are not 

 attached to the shell which they occupy, like the animals of 

 Purpura and Buccinum, but change from a smaller to a 

 larger one as their increase in size compels them. The small 

 Carcini with the last article of the posterior feet expanded into 

 an oar-like member are probably the Cancer depurator. Another 

 form (nvWapos) occurs in bivalve shells. Following as it does 

 the description of the Cancri just mentioned, it probably belongs 

 to the genus Carcinus ; but no Payurus is so found. Aristotle 

 afterwards speaks of those in bivalves as small white Carcini 

 (v. 13. 9) ; yet a few lines before they are said to be either Cari- 

 dion or Carcinion, Whether therefore they are small Anomura 

 or Macrura, or intended as members of both groups, it is not 

 easy to say : probably the latter is the correct view. Certain it 

 is that his Pinnophylax or Pinnotheres is the species now known 

 as Pinnotheres veterum. Several small Brachyura frequent the 

 large byssus of some Lamellibranchs and the cavities of Sponges. 

 In the latter locality Forskfd detected two species, Cancer triden- 

 tatus and C. dentatus. I do not know the grounds of Aristotle's 

 statement that they cast webs across these cavities, and thus 

 catch their prey ; it has, however, apparently suggested the 

 comparison of C. Bernhardus to a spider, to which it has some re- 

 semblance when, semiretracted, the feet are gathered close to 

 the head. 



The relations of these animals were a puzzle to Aristotle; 

 and the difficulty may be taken as a measure of the system, or 

 rather want of system, in his zoology. They are described 

 along with the Ostracoderma, to which he says they in some 

 way belong, as, though like Malacostraca, they occupy shells; 

 but having no organic connexion with the shell, passing even 

 from one shell to another, he considers them as intermediate 

 between the two groups. How strong seemed their affinity to 

 that with which their connexion is only accidental may be in- 

 ferred from their being thought to originate in the same way — 

 namely, from mud and sand. Even the fisherman's story, that 

 the Pinnotheres comes into being along with the Pinna, is 

 quoted, apparently with approval. 



In the preceding statement of the most recent opinions on the 

 identity of these forms, I have not alluded to the statements of 

 other authors, Greek and Roman, bearing upon the Crustacea, 

 partly because it seemed better to make clear the data given by 



