669 



MACLUREITE. 



MACRAUCHENIA. 



670 



The wood of M. tinctoria is the dye-wood called Fustic ; it contains 

 morine, a peculiar colouring substance ; its fruit is pleasant, and used 

 in North American medicine for the same purposes as the black 

 mulberry in Europe. According to Martius, both the other species of 

 the genus yield fustic in Brazil. (Lindley, Vegetable Kindgom.) 



MACLUREITE, Condrodite, Brueite, a Mineral, occurring imbedded 

 in rounded masses, the larger of which present occasional crystalline 

 appearances of rhombic prisms with dihedral terminations. Cleavage 

 parallel to the lateral planes. Fracture uneven. Hardness 6'5. 

 Specific gravity 3'15 to 3-25. Colour yellowish or brown. Lustre 

 vitreous. Becomes negatively electrical by friction. Transparent, 

 translucent. 



Infusible by the blow-pipe, but becomes colourless. With borax 

 fuses into a transparent glass, colouned by oxide of iron. Not affected 

 by acids. 



It occurs in New York and New Jersey, and also at Pargas. 

 Analyses No. 1, by D'Ohssor, from Pargas; No. 2, from New 

 Jersey, by Seybert : 



No. 1. No. 2. 



Silica 38-00 32-66 



Magnesia .... 54-00 54'00 



Oxide of Iron . ... 5'10 2'33 



Alumina .... 1*50 



Potash 0-86 2-11 



Fluoric Acid .... 4'09 



99-46 95-19 



MACO'MA, Leach's name for the Venus tennis of De Blaiuville, 

 and similar species. [VENERID.S.] 



MACHA'SPIS (M'Leay), a genus of Coleopterous Insects of the 

 section Lamellicomei, and, according to Latreille's classification, 

 belonging to the third division of that group, the Xylophili. The 

 genera Macraspii and Chasmodia constitute two closely allied groups 

 of the family Rutdida, the species of which inhabit the warmer parts 

 of South America, and are remarkable for the large size of their 

 scutellum. They are of tolerably large size (averaging about three- 

 quarters of an inch in length, or rather more), usually very smooth 

 and glossy, and often exhibit brilliant colours, green, brown, and 

 yellow being the most common hues observable in the various species. 

 There are some however which are of a glossy-black colour, and 

 others which have yellow markings on a black ground (Maeraspis 

 quadrivittata, Olivier). The body is of an ovate form (the head and 

 thorax having an outline continuous with that of the abdomen, or 

 nearly so), convex above and beneath. The sternum is produced 

 anteriorly into a pointed process, which projects between the anterior 

 pair of legs. 



In the genus Macraspu the mentum is longer than broad, slightly 

 contracted anteriorly, and without any fringe of hairs on the anterior 

 margin; the mandibles are almost triangular, and have the apex 

 pointed and notched ; the maxillae have several denticulations. 



The genus Chasmodia (M'Leay) is chiefly distinguished from 

 Macraipix by the obtusely terminated mandibles, which have no notch 

 at the extremity ; the maxilla; having a tuft of hairs and only two 

 denticulations, and the mentum being of a somewhat ovate form, 

 distinctly contracted towards the apex and furnished with hairs. 

 The claws of the tarsi are simple, whereas in Maeraspis one of the 

 claws of each tarsus, at least of the four anterior legs, is bifid. 



The insects of these two genera fly by day about trees, emitting a 

 humming noise, and feed upon flowers. Collections formed in Brazil 

 usually contain many of these insects. 



Dejean, in his ' Catalogue des Coldopteres,' enumerates 26 species 

 of Macraspii and 5 species of Chasmodia. 



MACRAUCHE'NIA, Professor Owen's name for a large extinct 

 Mammiferous Animal, referrible to the order Pachydermata ; but 

 having affinities with the Jluminantia, and especially to the Camelidte. 



The remains on which the Professor founded this genus included 

 two cervical vertebrae ; seven lumbar vetebrac, all more or less frac- 

 tured ; a portion of the sacrum and ossa innominata ; fragments of 

 the left scapula ; of the right radius and ulna, and right fore foot ; 

 the right femur nearly entire ; the proximal and distal extremities of 

 the right tibia and fibula ; and a metatarsal bone of the right hind 

 foot. These portions of the skeleton were discovered by Mr. Darwin 

 in an irregular bed of sandy soil, overlying a horizontal accumulation 

 of gravel on the south side of Port St. Julian, on the east coast of 

 Patagonia, and belonged to the same individual. 



Professor Owen observes that what is described as a perforation of 

 a single transverse process in a cervical vertebra is essentially a space 

 intervening between two transverse processes, a rudimental rib, and 

 the body of the vertebra!, and the Professor alludes to the manifestation 

 of this structure in the cold-blooded Saurians and in the Ornitliorhyn- 

 chiu. He observes that the Candida differ not only from the other 

 Kuminants, but from all other existing Mammalia, in the absence of 

 perforations for the vetebral arteries in the transverse processes of 

 the cervical vetebrae, the atlas excepted ; and though it is true that in 

 other Mammalia the two transverse processes are manifested on each 

 Hide with their extremities united by a distinct cartilage, this appears 

 in the fcctal state only, for the cartilage afterwards becomes ossified 

 Mid anchylosed to them. After referring to the structures of the 



inferior transverse process, or its representatives, in the Hippopotamus, 

 the Marsupials, and the Giraffe, Professor Owen proceeds thus : "In 

 the long cervical vertebrae of the Camel and Llama the upper and 

 lower transverse processes are not developed in the same perpen- 

 dicular plane on the side of the vertebra;, but at some distance from 

 each other ; the lower transverse processes (f.y. 1, a) being given off 



Cervical Vertebra (I, 2) of ifacramhenia, and (3, 4) of Amhcnia, one-half 

 natural size. 



from the lower part of the anterior extremity of the body of the 

 vertebra ; the upper ones (fig. 1, 4) from the base of the superior 

 arch near the posterior parts of the body of the vertebra. The extre- 

 mities of these transverse processes do not become united together, 

 but they either pass into each other at their baae or continue through- 

 out life separated by an oblique groove. This groove would not 

 however afford sufficient defence for the important arteries supplying 

 those parts of the brain which are most essential to life ; and accord- 

 ingly the vertebral arteries here deviate from their usual course, iu 

 order that adequate protection may be afforded to them in their 

 course along the neck. From the sixth to the second cervical vertebra 

 inclusive in the Aticheniai, and from the fifth to the secoud inclusive 

 in the Camdi, the vertebral arteries enter the vertebral canal itself, 

 along with the spinal chord, at the posterior aperture in each vertebra, 

 run forwards on the outside of the dura mater of the chord, between 

 it and the vertebral arch, and when they have thus traversed about 

 two-thirds of the spinal canal they perforate respectively the superior 

 vertebral lamina;, and emerge directly beneath the anterior oblique or 

 articulating processes, whence they are continued along with the 

 spinal chord into the vertebral canal of the succeeding vertebra, and 

 perforate the sides of the anterior parts of the superior arch in like 

 manner; and so on through all the cervical vertebra; until they reach, 

 the atlas, in which their disposition, and consequently the structure 

 of the arterial canals, resemble those in other Ruminants. The two 

 cervical vertebra; of the Macrauchenia present precisely the structure 

 and disposition of the bony canals for the vertebral arteries which 

 are peculiarly characteristic of the Camelidoe among existing Mam- 

 malia." Fig. 2 shows the groove and orifices of the canal for the 



