1896. THE LOBSTER. 41 



His intention was inoperative, because he had been forestalled by an 

 earlier writer. J. C. Fabricius, in his various writings, of which it 

 will be sufficient to cite the "Species Insectorum," 1781, and the 

 " Entomologia Systematica," 1793, consistently places Astacus marinus 

 [Cancer gammanis, Linn.) as the first species of the geuMS Astacus, giving 

 to A . flnviatilis invariably the second place. There can therefore be 

 no reasonable gainsaying that he made the European lobster, and not 

 the river crayfish, the type. From this it follows, in accordance with 

 explanations given as well by Dr, Herrick as myself, and recently 

 accepted by Dr. Arnold Ortmann, that the generic name of the 

 lobster is properly Astacus, and that of the European crayfish 

 Potamobins. 



Dr. Herrick discusses very fully the structure and growth of the 

 lobster's shell, and the manner of its exuviation. He controverts a 

 prevalent opinion that the carapace is ruptured along the middle line 

 to assist the process. " There is normally no rupturing of the shell 

 in any part in the course of the molt. The entire exoskeleton, with 

 the hnings of the eesophagus, stomach, and intestine, comes off as a 

 whole, and the animal leaves it by drawing the anterior parts of the 

 body backward, and the abdomen and its appendages forward, 

 through an opening made by the elevation of the carapace." A foot- 

 note explains that the hning of the alimentary tract is, of course, 

 ruptured. Also, though the carapace remains unbroken, it is made 

 more pliable during the preparation for the moult by the absorption of 

 the lime salts of the shell along the median line and other areas. 

 The most surprising part of the process is the extraction of the 

 gigantic muscles of the large claw through the narrow joints of the 

 arm. They have to undergo distention and compression to an 

 extraordinary degree. Their passage is compared to the drawing of 

 a wire through the contracting holes of a draw-plate. " The muscles 

 appear to be stretched out like a stick of candy, but, apart from their 

 elasticity, they are probably aided in accomplishing this by the 

 removal of water from the blood. The parts are very much distorted 

 immediately after they are free, and are quite hard, but they soon 

 take up water and assume their natural form, with a proportional 

 increase in size." 



Of the gastroliths Dr. Herrick says that they, " though often 

 called crab's eyes, are found only in the crayfish and lobster, so far as 

 known." This is probably said in forgetfulness of the account 

 given by Patrick Browne of their occurrence in the land-crabs of 

 Jamaica. Dr. Herrick carefully discusses their origin, structure, and 

 use. After considering most of what has been written on the subject, 

 he deems it Hkely " that the gastroliths in the lobster represent the 

 lime which has been removed by absorption from the old shell pre- 

 paratory to the molt, as well as, possibly, a small amount which may 

 have entered the blood from the food during the molting period." 

 Such a theory of their origin may, perhaps, dispense with any further 



