362 bulletin: museum of comparative zoology. 



Tarentum Mytilus solen, and gave a tolerable figure. Two years later in the 

 secoud volume of Poll's Testacea utriusque Siciliae the author named the shell 

 Tellina togata and figured it. In the same year it reappeared in the English 

 translation of Ulysses' Travels. The Mediterranean species, which must take 

 the name of Solemya solen (Ulysses), was named S. mediterranea by Lamarck in 

 IS 18, and was the subject of a remarkable anatomical study by Deshayes in his 

 Mollusques de I'Algerie. In this work the shell is admirably figured, and an 

 excellent photographic figure of the interior appears in the plates to the Mol- 

 lusques marius du RoussHlou. 



In this connection it may be stated that no complete account of the hinge of 

 this genus is, so far as I have been able to discover, anywhere to be found in 

 print. Also that the hinge is by no means uniform in all the species, but by 

 means of it they can be divided into groups. 



Solemya australis has a very archaic type of ligament, as perhaps might be 

 expected from the archaic features of the anatomy and the sitm which the genus 

 usually frequent. Yet it is true that the paleozoic relatives of this group have au 

 external ligament. In the present species in a fresh state the periostracum and 

 true ligament are continuous over the hinge and the gap between the two valves, 

 as was the original protoconch in the embryo. The only distinction perceptible 

 is that the ligament is a little darker in color. The hinge line is entirely freefrora 

 any trace of provinculum or teeth. The functional part of the ligament is amphi- 

 detic, extending on both sides of the beaks and included in a deep groove between 

 two shelly laminae forming the dorsal calcification of the valve, the ligament 

 extending beyond the enclosing laminae both before and behind. If dry and 

 broken, the section of the ligament has a glassy look, like a piece of glue. Under 

 the middle of the ligament and between it and the inner lamina of attachment 

 (or nymph) is the resilium, much thicker than the ligament, and of a more fibrous 

 constitution and darker color. The resilium also extends backward of the beaks, 

 but not so far as the ligament with which it is intimately cemented. The liga- 

 ment extends in advance of the nymph and beaks, throwing down on the inner 

 surface of the valve an oval, brown lobe like a dab of varnish. In S. parkinsoni 

 Gray, this lobe is straiglit, elongated, and narrow. 



The inner lamina or nymph is heavily reinforced with shelly matter, so as to 

 bear the strains incident to the resilium which is seated upon it. As the two 

 valves are not so closely adjacent as in most modern bivalves, the resilium is 

 visible where it crosses the gap between the two valves to join the opposite 

 nymph, and in an unbroken specimen an internal view of the hinge shows in 

 brown, against the whiter shelly matter, an X-siiaped mass composed of the 

 soldered ligament and resilium, the anterior arms of tlie X being formed by the 

 two ligamcntal lobes above described. The nymph on each side may be sus- 

 tained by a prop or rib of sliclly matter at each end, and between these ridges 

 may be situated the posterior adductor, but in S. auttralis only the anterior ridge 

 is developed, extended about half-way across the valve, much like the rib in 

 Siliqua. The posterior muscular impression is directly behind this rib. In 



