INDUSTRIAL PROGRESS DURING THE YEAR 1874. cxlix 



Interesting new Crustacea have been dredged by the Chal- 

 lenger party, including a blind, deep-sea Astacus-like form, 

 and a Tanais, also blind, together with a new Nebalia from 

 the Bermudas. Mr. Harder describes a new crustacean from 

 Lake Superior under the name of Asellopsis, differing in some 

 important characters from the common fresh-water " sow- 

 bug," Asellus. A number of new Phyllopod Crustacea have 

 been described by Dr. Packard in the Sixth Report of the 

 Peabody Academy of Science ; and he gives a synopsis of the 

 American forms in the Annual Report of Hayden on the 

 Geology of the Territories, with remarks on their singular 

 habits and distribution. The fossil Crustacea of Bohemia 

 have been further discussed by Barrande in a new volume 

 of his Paleontology. A number of remarkable trilobites, and 

 other ancient Crustacea allied to the modern Nebalia, are de- 

 scribed and figured. 



The mass of published matter on the Insects, or Tracheatn, 

 is enormous, especially the systematic works and shorter 

 papers. Perhaps the most important paper relating to the 

 physiology of insects is one by Plateau on the phenomena 

 of digestion, the result of a great number of dissections and 

 experiments. He finds that when the salivary glands are 

 not diverted from their primitive function to become silk or 

 poison glands they secrete a neutral or alkaline liquid, pos- 

 sessing, at least as regards one pair, the property character- 

 istic of the saliva of vertebrate animals of rapidly transform- 

 ing starch matters into soluble and assimilable glycose. The 

 change is effected in a posterior dilatation of the oesophagus. 

 At this place results, in the carnivorous insects, a transfor- 

 mation of albuminoid matters into soluble substances like 

 peptone ; and in vegetable-feeding species an abundant pro- 

 duction of sugar out of the starchy matters eaten. When 

 digestion has taken place in the oesophagus, it is submitted 

 to an energetic pressure in the gizzard, or proventriculus, 

 which is armed with teeth. It thus seems that this is not 

 an apparatus for crushing the food, but for expressing the 

 liquid from the food triturated by the jaws. In the stomach, 

 or middle intestine, as Plateau calls it, the food is again sub- 

 mitted to the action of an alkaline or neutral liquid, secreted 

 by local glands, present in the Orthoptera, or by a great 

 number of small glandular ccecua, as in many beetles, or by 



7* 



